The present invention concerns a device for protecting bearings of pulleys in belt drives from entry of dust and foreign matter. The a bearing with which the invention would typically be used has a fixed inner ring, rigidly fitted around a supporting core, and a rotating outer ring, anchored in an engagement housing provide within a pulley. The pulley has a fastening collar in which there is said engagement housing. A connecting disc-shaped flange extends coaxially around the fastening collar substantially in a plane perpendicular to the axis of the collar. The bearing has a cylindrical rolling portion circumscribing coaxially the fastening collar and the disc-shaped flange with an outer working area arranged to act in contact relation with a driving belt.
In particular, the device of the present invention is intended to be used on belt drives of the type mounted on motor vehicle engines and the like.
As known, in motor vehicle engines and the like, the actuating of components such as the a.c. generator and the cooling pump, the pump of the power steering, the compressor of the air conditioner and others, is provided by a driving belt extending in a closed loop around a driving pulley, driven by the engine itself, as well as around different driven pulleys arranged for rotating the above said components. Moreover, in a lot of cases there are provided one or more idle pulleys, used as simple slide guide pulleys and/or associated to known belt tensioners to give a constant tensioning to the belt itself, to assure a uniform transmission of motion in absence of slipping actions.
These idle pulleys usually are mounted on respective supporting pivots with the interposition of ball or roller bearings. More particularly, each bearing has its own fixed inner ring, rigidly fitted around a supporting core carried by the stationary structure of the engine or by a movable arm which may be part of the belt tensioner as well as a rotating outer ring, anchored in an engagement housing within a fastening collar making it part of the pulley. A disc-shaped flange radially projects from the fastening collar of substantially cylindrical shape, said disc-shaped flange supporting, in a radially outer position, a cylindrical rolling portion which circumscribes coaxially the fastening collar and has an outer working area arranged to act in contacts relation with the driving belt.
In consideration of the aforesaid, it is pointed out that the bearings mounted on the above said pulleys are subjected to working situations that expose them to risks of premature wearing and/or seizing owing to the great quantity of dust, deposits, welter and other foreign agents to which they are exposed.
It is clear that such a situation represents a great problem, since in consequence of the bearing seizing, the driving belt breaks owing to the strong sliding of the same on the locked pulley.
The attempts made up to now to overcome said type of problem are potentially directed to use protecting elements secured to the supporting central core of the bearing in order to protect this latter from the contact with the above mentioned foreign agents.